Method of and means for propelling ships



Aug. 11, 1931. F. w. GAY

METHOD OF AND MEANS FOR PROPELLING SHIPS Filed April 15,- 1928 ATTORNEYSPatented Aug. 11, 1931,

v UNITED STATES P ENT- OFFICE FRAZER w. GAY, or NEWARK, new JERSEYMETHOD OF Am) MEANS l Application filetl April 13,

h It is well known ,that'ships ordinarily are propelled by paddle Wheelsor by screw propellers. The screw propeller method is the most commonand is attended with many disadvantages of which the following are themost important; The over-all efficiency expressed in ratio of tow-ropepower to indicated engine room power, is seldom great: v er than fiftyper cent. The driving mechanism, if direct, is large and heavy. If highspeed turbines are used as a source of power, mechanical and electricalspeed reducing means are required in transmitting this power to thenecessarily relatively slowrevolving propellers. i I

Furthermore, it is known that ships like any other object forced throughWater, moving at high speeds produce waves which in crease the pressureorresistance on'the bow of the ship and impede movement thereof. Suchwaves travel at the speed of-the ship, and at distances from crest tocrestwh-ich increase rapidly with the speed fromapproximately eightyfeet at twelve knots to five hundred feet at thirty knots.

Calculations show that a pressure equal to six inches of water head atthe stern of a cargo boat in excess of' the pressure at thebow'issufficient 'to drive such boatat its usual speed of ten totwelveknot sper hour,

while in the case of lar e high speed passenger ships, like theaum'tomz'a, 'a differ- 'ence inpressure equal to a head of three feet"of water or even'more would be required; One object of my invention isto provide a noveland improved method ofship propul sion consisting increating such a difference between the pressures of the water at the bowand the stern of a ship and'utilizing said 40 pressure difference forpropelling the-ship thereby eliminating the. above-mentioneddisadvantages of screw-propeller propulsion;

1 Another object is to provide a method of propelling ships whichconsists in producing a pressure wave at a point in advance of the bowof the ship sov that the ship may 7 take entrance in the troughfollowing such pressure wave. It'is evident at once, that if the shiptakes its. entire entrance in; the

FOR PROPELLING srrrrs 1928. Serial No. 269,688.

anotherwave which will counteract on the,

previous pressure. wave. It is necessary, therefore, to produce apressure Wave of sufficient magnitude that after a part of its troughhas beenneutralized by the wave of entrance of the ship, there remainsenough trough to balance the skin friction of the ship and sterncavitation.

Another object is to provide novel and improved means for reducingthehydrostatic pressure at the bow of a ship.

ther objects are to provide novel and im- I proved means for producingsuch pressure waves in advance of the ships bow; to provide such meanswhereby the distance ahead of the bow at which such pressure waves areproduced may be varied; to provide a method of ship propulsionconsisting in imparting energy to the water at a point in advance of thestern or exit portions of a ships hull to increase the hydrostaticpressure or head at the stern; to provide means for so impartingenergyto the water ahead of the exit portions ,7 of'a ships hull, and toobtain other advan-' tages and results as will be brought out by thefollowing description.

' In the accompanying drawings I have schematically illustrated mymethod of and means for propelling ships, but it should be understoodthat this is primarily for'explain- 'ing the principles of the inventionand that many modifications thereof may be made by those skilled intheart without departing from the spirit or scope .of the invention.

Referring to said drawings in which corresponding and like parts aredesignated throughout the several views by the same referencecharacters, 9 Figure 1 is a schematic plan view of a ships hull showingthe principles of one form of my method and means; V

FigureQ is a longitudinal sectional view taken on the line of Figure 1;i a 5 Figure 3 is a plan view of a modified form of the invention; and aI Figure 4 is a similar view of a further modification.Specificallydescribing'the form of the invention shown in Figures 1 and2, the reference character 1 designates the hull of a ship having sidesof entrance 2, 2 and a projection 3, a pipe in the form shown extendingforwardly from the bow below the normal water level 4, and formed with adownwardly directed opening 5. This pipe is connected at 6 to anysuitable source of compressedair. In operation initially slow motion isimparted to the hull in any suitable manner by a screw propeller, andcompressed air is eject-ed in a continuous stream from the opening 5.This creates a pressure waves 7, 7 at each side of the hull and at apoint ahead of the bow and following troughs 8, 8 which extendsthroughout the length of the entrance sides 2, 2. The ship thereforetakes its entrance in said trough the surface of the water in which isso low that only slight impedance by the water to forward movement ofthe ship is produced. The resistance by the water .to movement of theship is thus materially less than it would be according to knownpractice. This pressure wave gradually flattens out or decreases inheight shown by dotted lines 921-1111 10, and as the ship travelsforwardly is influenced forwardly by the pressure of the wave on thestern 11 as indicated at 12.

The invention may be utilized as an auxiliary to ()I'dlILdI'y screwpropeller n'opulsion, the reduction in hydrostatic pressure at the bowcaused by the air emitted from opening 5 decreasing the resistance bythe water to the force exerted by the propeller; but the air may beejected from the opening 5 in such volume and at such ruessure that thepressure Wave when the stern reaches it as at 12, has

sufiicient head in excess of the pressure at the bow to exert apropelling force on the ship.

In Figure 2, Thave shown further means to increase the energy in thewave ust before the stern reaches it, said means comprising an opening13 in the shlps hull connected to the an supply pipe 6. By this meansthe height .or pressure head of the wave at point 14 is increased andthe pressure thereof imparted to the stern at 12. If this increase inpressure head is only slight, it will serve only to reduce the retardingeffects on the hull of stern cavitaltion, but the pressure may be sogreat as to exert 'a propelling force on the stern and drive the ship.The distance between the openings 5 and 13 must be so correlated to thelength and the speed of travel of the ship, that the air pressure willbe applied at the proper point 14.

It may be desirable to provide means for varying the distance ahead ofthe entrance surfaces 2, 2 at which the pressure wave 7 is produced sothat the pressure wave is located in advance of the hull of the ship, adistance proportional to the square of the speed of travel of the hullwhich will vary at different times, and for this purpose I may make thepipe 3 slidably adjustable through the bow, or the projection may bemade in tegral with the hull and the opening 5 formed at differentdistances from the entrance surfaces 2, 2, as shown in Figure 8, or aplu rality of openings any one of which may be used, can be provided.

It is also possible to provide for the hull. taking entrance in aplurality of stages, as shown in Figure 41-, where two projections 15and 16 of different widths connected by entrance surfaces 17, 17 areprovided. The projections 15 and 16 have respective openings 18 and 19to eject compressed air. The pressure wave 20, produced by the air fromopening 19 is partially neutralized by the first stage of entrancetaking by the surfaces 17, 17, and the pressure of said wave is thenincreased by the air from opening 18 to form a trough in which thesecond stage of entrance is taken by the surfaces 2, 2.

I do not desire to be understood as limiting myself to the precise formof taking entrance illustrated, as it is possible. to make the bow ofthe hull shallow and take entrance in the direction of draft only inthe:

wave troughs.

By moving the openings 5, 13, 18 and 19 forwardly-or astern, I maycompensate for the changes in wave length i. e., distance be tween thecrests of the wave, which varies after it has once been started by othermeans] I do not wish to be limited to the use of compressed air forcreating the above-mentioned pressure waves. I may for instancedischarge a mixture of air and gas or air and oil vapor in the form of,a succession of huge.

bubbles and explode these bubbles immediately after their emission,thereby creating a series of closely spaced points or zones of pressure.Such a succession of zones of pressure willgive substantially the sameeffeet as the jet of air.

Having thus described my invention, what I claim is:

1. A ships hull having a forward projection from its bow submerged inthe water, and means carried by said projection to produce a pressurewave in advance of the bow, and means for adjusting the last-named meansto vary the distance between the crest of said wave and the bow of thehull.

2. A ships hull having a forward projection from its bow submerged inthe water and exit surfaces, means carried by said projection to producea pressure wave in advance of the bow, means for imparting energy to thewater ahead of said exit portions to increase the hydrostatic pressureon said exit portions, and means for adjusting said means relative toeach other and the sh1p in accordance with the speed of travel of theship.

3. A ships hull having entrance surfaces, and means for producing a,pressure wave at a point ahead of said entrance surfaces of said hull adistance proportional to the square of the speed of said hull so thatsaid entrance surfaces take entrance in the trough following saidpressure wave.

4. The method of propelling ships consisting in establishing a pressurewave at a point ahead of the hull and adjusting thedistance of said Wavein advance of the hull in proportion to the square of the speed oftravel of the hull. v

FRAZER W. GAY.

